Oh, hey, just a quick question: Are there any good substitutes to thermal adhesive? I don't have any right now... and I kind of want to get this laser put together. I have no other means of sticking a heatsink to my driver besides by using thermal compound from radioshack. Should I just thermal-compoundly stick some aluminum to my driver and then put some heat-shrink-tubing around it or something?

Jib's drivers (at least the one you're using here) is based on an Lm1117. My sense is that this is a DDL type circuit - IE, the IC is used as a constant current source. Which means it has a resistor set to deliver 1.3A

So why would you get more, ever?

I understand that you *could* get more if you actively changed the resistor to provide for a higher value by means of the 1.25/X calculation. But obviously OP hasn't done that, otherwise he wouldn't have asked this question. So what IS going on here?

These are set to the max the IC can do, in my test this is 1.3A without heatsinking and 1.5-1.6 with GOOD heatsinking. I do not have resistors to set them to anything else. Its like Southwest Airlines, its cheap because I use 1 set of parts for all of them (allows for volume discounts for the parts). I do have a 1.8A driver in the pipeline though, Im hoping to have those available sometime next week.

Well, I was wondering the same thing myself... because the resistors are two 1 Ohm resistors and they look like they are in parallel... two 1 Ohms would be .5 Ohms, which would yeild 2.5A, which is far too much. What's the circuit structure on these?

Jib:
When you say you set them to the max the IC can do, I'm a little bit confused still. You're still relying on that 1.25 / X equation, aren't you? So isn't there a "set current", even if that's not exactly 1.3A?

EDIT: Wolfman beat me to essentially the same question. If the drivers are wired to *try* for 2.5A, then how are they constant current sources? Is it really ok to rely on the inherent current restrictions of the IC to accomplish current limiting? (maybe it IS, I don't know, that was a legitimate question)

EDIT (again): Question #2, why does the IC suggest that it's a 117, not a 1117 ?
Subtle difference, but the 117 isn't LDO and the 1117 is - I always assumed these were 1117 based drivers until I looked that the photos.